Method of tanning hides and skins



Sept. 22, 1931. A HOYT METHOD OF TANNING H IDES AND SKINS Flled Jan 3 1930 a tto i'i'iiy though certam of hides, or skins,

Patented Sept. 22, 1931 PATENT OFFlCE AARON new, or

BAYER-HILL, MASSACHUSETTS,

L. WOBTKEN, 0E HAVERH ILL,

ASSIGNOR OF ONE-HALF 1'0 SPENCER MASSACHUSETTS METHOD OF TANNING RIDES AND SKINS Application Med January 8, 1930. Serial No. 418,18t.

The present invention relates to methods of tanning hides, skins and the like and, features thereof are valuable in connection with the tanning of all kinds whether raw or pickled, tender or strong, the 'inventionfinds especial utility in connection with the tanning of very tender hides and skins such. as the grains of shee skins, as grains or skivers. Heavy sheepskin, as is well known, is usually split .into two or more layers. The layer next to the flesh of the animal, known as the split, is the fibre part and is strong enough to withstand considerable abuse without damage. The terms hide, skin, or their equivalents,-t'o avoid circumlocution, will include all such articles, including hides, skins, fieshers, grains, skivers, splits, and so on.-

The grain layer is practically without fibre, so is very tender and tears or depletes easily. The strong, commonly tanned -m quite large, rotating drums, rovided with internal pins or radially-d sposed vanes.' These pins or vanes pickup .the hides as the drum rotates,-and

a carry them around along the inside; of the methods of tanning, to the end drum. After rising to a considerable height, they drop back'into. the tanning liquor. Skivers can not be subjected to this treatment because, bein so tender and of short fibres, they would om'erapidly torn or otherwise mutilated. They are, accordingly, merely deposited m a large paddle vat; t and the 11 nor containing e tanning liquor, is caused, in any desired way, as by a pa dle wheel, to circulate in the vat and 1n and out between the hides. This process is, howevelr, very time consuming and uneconomica. v It is, therefore, an object of the present invention to improve upon present-day I that the cost of hides shall be lessened, the

of production time required to produce them greatly reduced, and the equipment necessary to their production made very much smaller, all these objects being1 accompanied by a superior product. T e invention, though not -tanning of soft hides or skins,

known in the trade or flesh-side, splits are rapidly into arc of swing,

limited thereto, finds particular value in the like skivers.. With the above ends in view, a feature of the invention resides in violently throwing the hides freely back and forth in the tanning liquor, through a substantial arc of swinging movement, preferably in engagement with a member, such as a cleat or shelf, against which the hides frictionally engage and over which they tumble. If the hides are strong and fibrous, they may, in addition to'the swinging movement, be subjected to a substantial fall also, but the fall should be very small for tender hides. The frictional engagement, in the case of tender hides, furthermore, should be such as not to impose too great a strain upon the skins.

The utility of the present invention is not, of course, dependent upon the existence of theories, whether accurate or inaccurate, to account for the observed phenomena. It is suflicient to describe and illustrate the invention as it has been found to work in practice. The theory of the operation is, however, probably as follows. During the violent throwing of the hides back and forth, they are maintained in more or less opened out condition, particularly at each-reversal of movement of the hides. The hides, consequently, become exposed di erent portions of the tanning liquor. The result is that the liquor penetrates the hides, the'spent liquor in immediate contact with the hides becoming continuously and rapidly moved away from the hides as soon as 1t parts with its tanning quality.

It has heretofore been proposed gently to oscillate hides back and forth in the tanning liquor,.but this proposal has not been accompanied b a violent throwing of the abovedescribe character, 'through a substantial nor by a frictional engagement of the hides during their swing. The adreely and Y vantages of the present invention will be reciated from the fact that hides treated in accordance with this method become completely tanned in from one-and-one-half to two hours; while other methods, particularly those for treating tender hides, require at least two days treatment. Hides tanned according to the method of the present invention over so much shorter a period of time, furthermore, have a smoother and tigsliter grain.

ost hides, including sheepskins, contain their natural animal fat or grease, and it becomes necessary to remove these substances before tanning, if quality leather is to be produced. This is effected on some hides by subjecting them to pressure, or to some other treatment that strong hides can withstand.

Skivers, however, can not be pressed or otherwise treated in this manner, as they would thereby become reduced to a mere pulp. It is customary, therefore, to tan the skivers without first degreasing them, the tanning process itself causing a drying up of some of the greases. After the skins or grains are tanned, the remainder of the grease is subjected to a degreasing process of another nature.

According to a further feature of the present invention, however, the hides may be degreased, prior to tanning, in the same manner .as-they are tanned, merely using a degreasin'g fluid instead of the tanning liquor. This is because neither. the degreasing nor the tanning process imposes any physical inugtupon the hides.

her and further objects will be explained hereinafter and will be particularly pointed out in the appended claims.

The invention will-now be more fully ex plained in connection with the accompanymg drawings, in which Fig. 1 is a view, in section, of a machine adapted, for the'carrying out of the method of the present invention; and Fig. 2 is a fragmentary view, upon a largerscale, of a detail of the mechanism shown in Fig. 1, this detail constituting, in itself, no part of the present invention.

The method of the present invention may be carried into practice with the aid of many different kinds of mechanisms, one such mechanism being illustrated in the drawmgs, 1n conformity with the requirements of the patent statutes. The hides 2 are shown contained in a drum 4 having perforations 6.

The drum 4 may be rocked or swung back and forth about an axis 8 within an outer, statlonary drum 10. .The tanning or other liquor is poured into the outer drum 10 through an outer door 12. The liquor flows mto the inner drum 4 from the outer drum 10 through the openings 6; The hides are introduced into the inner drum 4 through an inner door 14. The inner door 14 is maintained closed durin the oscillations of the inner drum 4, but t e outer door 12 may be kept open to admit cold air from the outside for coohng purposes. It is of advantage to carry away the heat during the tanning process, for if the temperature were too high, the skins might become damaged. The inand forth about the axis 8. The cleats or shelves 16 engage the hides at each swinging movement and partly rub past the hides, partly carrying the hides upward a short distance along one side 18 of the circumference of the drum 4. If carried too far up, the hides then drop or are thrown a short distance back into the liquor. The drum 4 is then reversed and the cleats 16 rub past the hides in the opposite direction and carry the hides upward a short distance along the other side 20 of the circumference of the drum. At each reversal, the drum is rotated through at least one revolution, in order to afford the cleats 16 an opportunity to perform their function properly. This aflords sufiicient violence for more or less throwing the hides back and forth through the drum open condition. The violence is not su ciently great, however, to injure the skins. The operation is continuous and without cessation, causin the tanning liquor to move rapidly an deeply into contact with fresh parts of the hides, and as rapidly to move away therefrom, and to penetrate into every hidden ortionof the hides. This is quite a di erent method from that employing a continuously rotat ing drum, in which the skins tend to rotate -more or less in unison with the liquor, af-

fording no opportunity for the skins to become rapidly separated from the portions of the tanning li uor with which they happen to contact. T e skins are perfectly loose and separated from each other throughout the tanning o ration- As a result of the present metho the hides become thoroughly tanned in a fraction of the time ordinarily required by present-day processes.

At each reversal of movement, furthermore, the tanning liquor is believed to be driven with considerable force from the outer drum 10, through the openings 6, in the form of jets, against the hides in the drum 4. The reversal of movement of the drum 4 thus aids in this additional manner to cause the tanning liquor to penetrate deeply into between the skins and the interior wall of the drum 4. The provision of the openings 6 is not, however; essential to the operation of the present invention, as this novel method may -be carried out in a single, imperforate drum 4, and without employing the outer drum 10.

According to present-day practice, the tanning ingredients are mixed together and added a little at a time, in more and more concentrated feeds, and in different parts of the tanning container, so that the tanning liquor may expend its strength and tan the hides gradually, without case-hardening them, and without drying up the fibers to the extent of burning or shortening them. The method of the present invention makes such precautions unnecessary, as it is found possible and practicable to introduce the whole tanning mixture at a single position of the machine,-through the open door 12, for example, at one and the same time, the machine being in motion. This is probably because, in the first place, the repeated reversals serve to distribute the liquor with extreme rapidity, so that the solution becomes uniformly distributed in very short order. More important still, however, anyparticular portion of the tanning liquor re-.

mains in contact with any particular portion of ahide for only a very small fraction of a moment, as before described.

For the tanning of strong skins, as has before been stated, the drum 4 may be of considerable diameter. When tanning tender skins, however, the drum should be small enough so that the fall of the skins should be very small. Indeed, as has been described above, the skins are thrown from side to side,

rather than carried up and allowed to fall from any considerable height. It is found that a diameter of between three and four feet for the drum 4 is very serviceable for the'tanning of ordinary skivers. When tanning tender skivers, the cleats 16 should be of such a nature as not to tear the skins. A good length of drum is about eight feet.

Though not essential to an understanding of the invention, one form of reversing mechanism, illustrated in Fig. 2, will be described, for completeness. The drum 4 may be provided, about the axis 8, with a bevel gear 22, meshing with bevel gears 24 and 26. The bevel gears 24 and 26 are loosely mounted upon a shaft 28, driven from a motor 30. Alined with the shaft 28 is a threaded rod 32 upon which is threaded a nut 34. The line of separation of the shaft 28 and rod 32 is indicated at 36. The gear 26 is fixed to the rod 32, so as to cause them torotate as a unit. A twopart clutch 40, 42 is carried by a sleeve 44 upon the shaft 28. The sleeve 44 is free to slide upon the shaft 28, but is compelled to rotate with the shaft by a spline 46. The sleeve 44- may he slid back and forth along the shaft 28 by a lever 48, connected by a rod 50 with the nut With the parts occupying the illustrated positions, the clutch 42 engaging a cooperating clutch 52 carried by the gear 26, the bevel gear 22 is rotated in the direction of the arrow, causing the drum '4 to turn in the same direction, The nut 34 is, at the same time, moved over to the left, as viewed in Fig. 2. After suflicient tension has been taken up by a spring 54, the lever 48 will snap over to the left, causing unclutching of the clutches 42 and 52, and causing the clutch 40 to engage a clutch 56 carried by the gear 24. The movement of the bevel gear, and consequently of the drum 4, will now be reversed. The rotation of the bevel gear 26 will, therefore, cause the nut 34 to advance toward the right, and after the tension' of a spring 58 has been taken up, the lever 48 will snap to the right again, effecting reengagement of the clutches 42 and 52 and another reversal of the drum 4.

As before stated, the same steps may he carried out in degreasing the skins prior to the tanning operation. The complete tanning operation may, therefore, be somewhat as follows: I The drum 4 is first about half filled with skins or hides. A degreasing liquid of any nature is poured into the drum 10 through the dOOr 12. Of course, if strong hides are employed, they may be degreased before they reach the tanning drum, hides, like grains'or skivers, may be treated to this initial degreasing step. The drum is then operated as before described for as long a time as may be necessary. The liquid is then drained at 60, and is replaced by a warm brine solution, and the skins subjected to the same process for a short period of time. This water is also drained. A cold brine solution is now added, for the purpose of preventing the skins from swelling, an also to open the pores of the skins to receive the tan.

According to a feature of the present invention, the tanning liquor may now be introduced in one operation and in the desired full-tan strength. It may, however, be added by stages, adding tan liquor at intervals, the drum 4 operating in the meantime. After the skins have become tanned, the

spent liquor is drained, and the contents hides that comprises first swinging the hidesbut tender and the liquid to back and forth in a degreasing liquid, and then tanning the hides.

2. A method of manipulating hides that comprises throwing the hides back and forth in a degreasing liquor to permit the degreasin liquor to penetrate freely into the hides, frictionally engaging the hides during their back-and-forth movement, throwing the hides back and forth in a washing liquid, frictionally engaging the hides during their back-and-forth movement in the washing liquid, throwing the hides back and forth in a tanning liquor, and frictionall engaging the hides during their back-and forth movement in the tanning liquor.

3. A method of manipulating hides during their treatment w1th various liquids during their manufacture into leather that comprises'placing the hides in a liquid, and causingslow relative movement between the hides and the li uid to produce gentle flexions of the hides and friction between their surfaces. Y

4. A method of manipulating hides during their treatment with various liquids during their manufacture into leather that comprises placing the hides in a liquid and violently throwing the hides and the liquid back and forth as a unit, thereby causing slow relative movement between the hides and the liquid to produce gentle flexions of the hides and friction between their surfaces.

5. A method of manipulating hides during their treatment with various liquids during their manufacture into leather than comprises placin the hides in a liquid and swin 'ng the ides and the liquid as a unit, there y causing slow relative movement between the hides and the liquid to produce gentle flexions of the hides and friction between their surfaces.

6. A method of manipulating hides during their treatment with various liquids during their manufacture into leather that comprises placing the hides in a liquid, and im artin a violent, swinging force to the hides an the liquid as a unit in opposition to the force of gravity, thereby causing slow relative movement between the hides and the liquid to produce gentle flexions of the hides and friction between their surfaces.

7. A method of manipulating hides during their treatment with various liquids during their manufacture into leather that comprises placing the hides in a liquid, causing slow relative movement between the hides the hides and friction between their surfaces, and mechanically producing a scraping action upon the surfaces of the hides which for the moment find themselves at the lower outer surface of the mass of hides.

8. A method of manipulating hides-during their treatment with various liquids durthe surfaces of the ment find themselves at the lower outer surproduce gentle flexions of ing their manufacture into leather that comprises placing the hides in a liquid, 1m artmg a violent, swinging force to the ides and the liquid as a unit in opposition to the force of gravity, thereby causing slow relative movement between the hides and the liquid to produce gentle flexions of the hides and friction between their surfaces, and mechanically producin a scraping action upon ides which for the moface of the mass of hides.

9. A method of manipulating hides during their treatment with various liquids during their manufacture into leather that comprises placing the hides in a liquid, causing slow relative movement between the hides and the liquid to roduce gentle flexions of the hides and friction between their surfaces, and forcing the liquid in jets into the hides during their slow relative movement.

10. A method of manipulating hides during their treatment with various liquids during theirmanufacture into leather that comprises placing the hides in a liquid, imparting a violent, swinging force to the hides and the liquid as a unit in opposition to the force of gravity, thereby causing slow rela tive movement between the hides and the liquid to produce gentle flexions of the hides and friction between their surfaces, and forcing the liquid in jets into the hides during their slow relative movement.

11. A method of manipulating hides during their treatment with various liquids during their manufacture into leather that comprises placing the hides and a liquid in a drum, and oscillating the drum about its axis to cause the hides to move through a large portion of a circle, thereby to produce slow relative movement between the hides and the liquid and gentle flexions. of the hides and friction between their surfaces, the walls of the drum mechanically roducing a scraping action upon the sur aces of the hides which for the moment find themselves in contact therewith.

12. A method of manipulating hides during their treatment with various liquids during their manufacture into leather that comprises placing a liquid in an outer drum in which is dis osed an inner, perforated drum, the walls o which are interiorly provided with longitudinally disposed projections, placing the hides in the inner drum, and oscillating the inner drum about its axis back and forth in the outer drum to cause the hides to move through a large portion of a circle, thereby to produce slow relative movement between the hides and the liquid and gentle flexions of the hides and friction between their surfaces, the walls and the projections of the drum mechanically moving the hides back and forth and producing a scraping action upon the surfaces of the hides which for the moment find themselves in contact therewith.

13. A method of manipulating hides during their treatment with various degreasing liquids during their manufacture into leather that comprises placing the hides in a degreasing liquid; causing slow relative move-- ment between the hides and, the de asing liquid to produce gentle flexions of t e hides and friction between their surfaces, placing the hides in a tanning liquid, and causing slow relative movement between the hides and the tanning liquid to produce gentle flexions ofthe hides and friction between their surfaces. a

In testimony whereof, I have hereunto subscribed my name.

' AARON HOYT. 

